Turbine construction



1 I STATES AIENT OFFICE. 1

Louis som mar, or xonxnns, NEW Yonx.

TURBINE consmnucrron.

To all whom it may concern: l

' Be it known that I, Loms JOSEPH Hnrr, a citizen of the United States, residing at Yonkers, in the county of Westchester and State of New York, have invented certain new and useful Improvements'in Turbine Constructions, of which the following is a specification.

This invention relates to steam turbine construction, its objects beingto efiect tight and durable seating of the buckets on thebucket-carrier disks, to minimize lateral deflection and vibration of the buckets when in use on their carrier disks, to minimize the liability of the present frequent cracking of the peripheral margins of the carrier disks, and to cheapen the cost ofmanu-facture of such turbinesp It is well known to all skilled in the .art that the bucket-carrier disks of steam turbines are subject continuously in use to expansion in some parts and almost instantaneous contraction in other parts, the expansions and contractions occurring with great frequency and very often in rapid alterna tion. In addition to the usual centrifugal.

and tangential stresses the bucket-carrier disks are subject/to stresses in consequence of becoming heated by the steam and of.

cooling; and when, for example, steam is shut off, the temperature of the buckets and of the peripheral marginal portion of the bucket-carrying disk becomes lower than the temperature ofcthe disk nearer the hub so that the peripheral marginal portion con tracts more rapidly than the more, expanded what is known in the art as hoop stresses f in then occasioningperipheral marginal central portion of the disk, thus causing with great frequency, causing crystallization of the outward portion "of" the disk" around its peripheral marginal portion and craclfing of the disk. It is alsolmownin the artthat the centrifugal tangential and hoop stresses in a bucket-carrier disk have constant uniform temperature and whenrunning at a high speed within the elastic limits of the material, is not so much subject to the stresses caused bythe expansions ang/ contractions mentioned above; but in pr ctice steam turbines are'subject 'to vari able station loadsfwhich automatically regulate the steam supplyand thereby. vary the heat to which the turbines are subject, with consequent frequent cooling, and it is due to the frequent alternate expansions, con- Specification of Letters Patent.

Patented Sept." 2, 1919.

, Application filed March 21, 1919. Serial No. 284,022.

tractions and crystallization of the disks that tend from the periphery of the disk inwardly toward the hub, the slots being of equal length; with integral disk projections between the slots; and with aplurality of buckets seated on .each disk projection.

Fig. 2 is a view partially in section and partially in elevation at line 2-2 of Fig. 1, and shows one of the buckets interlockingly seated onthe bucket-carrier disk and bonded thereto by welded metal.

the buckets at line 3-3 of Fig. 2; and

Fig. 4-. is a View showing the-interlocking members of a bucket and carrier disk spaced apart for convenience in lettering the inter-- v locking members.

In the drawings, the carrier disk 1.is

formed with an integral marginal flange 2 extending wholly around the disk and theperiphery of which is indicated by 3.- The inward face of this disk is formed with a circular groove 4 radially inward of and spaced apart from the periphery 3' with which the radially .outward and inward walls of the groove 4 are concentric, thus forming on the inward face of the flange an annular rib 5 the periphery of vwhichis a part of the periphery of the flange. The inward face of the rib 5 is about in line with a plane projected diametrically through the disk midway between its sides. The outer eripheral corner .of the carrier disk flange is 'beveled inwardly and-outwardly at '6.

lhe inward wall of the groove 4 is indicated by v7 and extends from the base of the flange toward the opposite side of the disk and to its junction with the inward and outward beveled wall 8. Thus the carrier disk is formed with two peripheral bucket-shank-seating walls 3 and7- of unequal diameters and with the intermediate annular rib 5 and the circular groove 4.

The shank 9 of each bucket is'reduced in v lateral thickness and formed on one side with an arcuate groove v10 to receive and interlock with an arced portion of the disk 7 rib 5; and with an arcuate rib 11 to fit in and interlock with an arced portion of the Fig. 3 is a cross-sectional detail of one of 7 carrier disk. The lateral bottom wall of the arcuate groove 10 is deep enough to receive the rib 5. The outward arced wall of the groove 10 overlaps and bears on the peripheral wall 3 of the carrier disk; The inward arcuate end of the shank 9 is downwardly and inwardly beveled at 13 and on the opposite side of the shank its side wall is inwardly beveled at 14.

In the assemblage indicated and described, the beveled walls 6 and 14 on one side and the beveled walls 8 and 13 on the other side form arcuate V-shaped spaces wherein metal 15 is welded in order to bond the bucket shanks in place on the disk carrier.

The buckets are by thedescribed means not only seated tightly in place on the carrier disk, but are seated in such a manner that they will not become loose.

In accordance with an important feature of this invention the carrier disk is provided with a series of approximately radially disposed thin slots 16 all of equal length and spaced apart one from another,

and severally extending from the periphery of the disk inwardly toward the hub, and inwardly beyond the lower ends of the bucket shanks, thus fOTIIHHg the peripheral marginal portion of the disk with a series of integral endwiseseparated. disk projections 17 on which I may mount any number of buckets in the way above described or otherwise. For perfectly balancing the disk and buckets, the slots are formed at equal distances apart, and at each side of the axis of the disk two of the slots are diametrically opposed one to'th other. The number of the slots 16 and bucket-carrying projections 17 may be varied, but such slots and projections will be of even numbers from two upwardly. In the drawings I show sixteen with six buckets anchored on each bucket-carrying projection 17, By this construction the several bucket-carrying projections are free to expand and contract one independently of another, whereby there are .minimized in the disk the tangential stresses due to the expansion and contraction of the disks at their peripheral margins, their peripheral margins becoming subject only, or approximately only, to

radial stresses.

What I claim is,-

1. The combination of a turbine bucketcarrier disk and a series of thereon radially mounted buckets, the disk being formed with aperipheral integral flange having on its in ard face an annular rib and an adjacen annular groove, and each bucket shank being formed with an arcuate groove and an adjacent arcuate rib, the flange rib being entrant inthe arcuate groove of the bucket shank, and the arcuate rib of the bucket shank being entrant in the flange groove; and the bucket shank being formed with two arcuate end walls one of which is seated on the periphery of the disk and the other of which is seated on the radial inward wall of the groom in thedisk; the

s0seated bucket shank being on each opposite side welded to the disk; and the bucketcarrier disk being slotted from its periphery inward to form separated integral bucketcarrying projections of the disk.

2. The combination in a turbine, with a bucket-carrier disk provided with a series of slots extending inwardly from the pcriphery of the disk and forming a series of bucket-carrying integral projections spaced apart one from another and severally free to expand and contract, of a bucket fixed on each projection.

In testimony whereof I have hereunto set my hand this 18th day .of March, 1919.

LOUIS JOSEPH HIRT, 

